Portable pressure relief system &amp; methods

ABSTRACT

A portable systems release fluid pressure with a cavity within a patient. These systems include a drainage catheter, a pressure-responsive one-way valve, and a fluid reservoir all adapted to be mounted in proximity to the cavity being drained. One system in particular is used in relieving intracranial pressure. This intracranial pressure relief system may include a headband to which are mounted the one-way valve and reservoir. The drainage catheter may have mounted thereon a cranium seal formed of a soft material that contacts the inner wall of a cranium bore hole. The cranium seal may have threads to facilitate advancement into the bore hole.

INCORPORATION BY REFERENCE

[0001] Applicant incorporates herein by reference any and all U.S.patents, U.S. patent applications, and other documents cited or referredto in this application or cited or referred to in the U.S. patents andU.S. patent applications incorporated herein by reference.

DEFINITIONS

[0002] The words “comprising,” “having,” and “including,” and otherforms thereof, are intended to be equivalent in meaning and be openended in that an item or items following any one of these words is notmeant to be an exhaustive listing of such item or items, or meant to belimited to only the listed item or items.

BACKGROUND OF INVENTION

[0003] Frequently it is necessary to drain fluids, particularly liquids,from various cavities in the body. For example, hydrocephalus ariseswhen the outflow of cerebrospinal fluid (CSF) is obstructed, whichcollects in the ventricles of the brain and produces an increase in theintracranial pressure. Left untreated, hydrocephalus can result inserious medical conditions, including subdural hematoma, compression ofthe brain tissue, and impaired blood flow. Excess intracranial pressureproduces symptoms such as walking or gait problems, incontinence,dizziness, and others. Hemhorrages and other causes also may result inan increase intracranial pressure and manifestation of the samesymptoms. Other cavities in the body also may collect fluid and causeexcessive internal pressure. Once diagnosed, the treatment is toeliminate the excess pressure by draining whenever fluid is causing itfrom within the body cavity.

SUMMARY OF INVENTION

[0004] This invention, with its several desirable features, issummarized in the CLAIMS that follow. After reading the followingsection entitled “DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THISINVENTION,” one will understand how the features of this inventionprovide its benefits. The benefits of this invention include, but arenot limited to: reduced costs associated with care giving for patientsrequiring drainage of fluids, convenience of use and enhanced mobilityof for patients requiring drainage of fluids, avoidance of catheterblockage, and enhanced patient mobility.

[0005] Without limiting the scope of this invention as expressed by theclaims that follow, some, but not all, of its features are:

[0006] One, this invention comprises a portable system for relievingfluid pressure from a body cavity of a patient. It includes a drainagecatheter for insertion into the body cavity. A first portion of thedrainage catheter may be at least 4 inches in length for insertion intothe cavity and a second portion that extends from the cavity.

[0007] Two, the invention may include a one-way pressure-responsivevalve with an inlet in fluid communication with an outlet of thedrainage catheter to permit pressure-regulated flow of fluid from thebody cavity through the catheter. The pressure-responsive valve has anoutlet that is at substantially atmospheric pressure and an inletinserted into the body cavity and at the pressure within the bodycavity. The valve opens and closes automatically in response to achanging differential in pressure between the inlet and outlet. Thevalve opens when the differential between atmospheric pressure and thepressure within the body cavity exceeds a predetermined difference andcloses when this differential is less than this predetermineddifference. In one embodiment, the pressure-responsive valve has a pairof membrane members that are in tension and form a slit opening that isnormally closed. At a predetermined difference, the valve opens andfluid flows between the membrane members and forces the membrane membersapart, to open the slit opening and allow the fluid to flow through thevalve until predetermined difference is no longer present and the valvecloses automatically.

[0008] Three, a reservoir may have an inlet in fluid communication withan outlet of the pressure-responsive valve so as to receive the fluidthat passes therethrough. The outlet of the catheter, the inlet andoutlet of the valve, and the inlet of the reservoir optimally are nearbyeach other so that there is essentially no hydrostatic pressure in thesystem affecting to flow of fluid from the body cavity. The distancebetween the outlet of the valve and the inlet of the reservoir typicallyis no greater than about 3 inches. The drainage catheter may have adistal end with drainage apertures therein, and this distal end of thedrainage catheter, reservoir inlet, and pressure-responsive valve are atsubstantially the same height. In one embodiment, the outlet of thecatheter, the inlet and outlet of the valve, and the inlet of thereservoir are substantially in a common plane.

[0009] Four, the drainage catheter, pressure-responsive valve, andreservoir may be connected to a mounting member that is adapted to bedetachably coupled to the patient nearby the body cavity. In oneembodiment, the drainage catheter, pressure-responsive valve, andreservoir are connected to a mounting member that is adapted to bedetachably coupled to the head or cranium of the patient. The drainagecatheter has a first end adapted to be inserted into a cavity in thecranium and a second end that is external to the cranium. The headbandmay include a first component sized to fit around the circumference ofthe patient's head, and a second component connected by opposed endsthereof to the first component and sized to fit over the top of thepatient's head. The first component may be adjustable to differentpatient head circumferences. The headband may include a releasable chinstrap to permit easy removal of the system. The headband may comprisesat least partially hollow member that functions as the reservoir. Thehollow member may be hoop-shaped. The reservoir may be detachablyconnected to the headband, for example, by a snap-type connector.

[0010] In this one embodiment, a connector adapted to be attached to thecranium holds the first end of the catheter in position in the cavity.This connector is also a feature of this invention, preventing leakageof fluid past it, so that essentially all the fluid flowing from thecavity passes through the catheter with essentially no fluid bypassingthe catheter and flowing around the connector. The outlet of thepressure-responsive valve is attached so as to receive the fluid. Theconnector may be integral with the catheter and may include a threadelement on an external surface of the catheter at or nearby the outletend of the catheter. The connector fits snugly into a hole in thecranium to prevent any substantial leakage of fluid past the connector,and it may have a passageway therein through which the drainage catheterextends so that the outlet end of the catheter is external to thecranium. The passageway may be formed by a substantially cylindricalwall member with a cleft therein. Typically, the connector may have abody with external threads thereon enabling the connector to be screwedinto the hole. This body is made of a material that deforms uponcompression and has a substantially truncated conical shape sized to fitinto the hole and compress as the connector is screwed to the hole. Sucha connector provides a substantially fluid tight seal between the holeand the body, with the passageway being constricted as connector isscrewed into the hole to provide a substantially fluid tight sealbetween the catheter and the passageway. In one embodiment, the body mayhave an enlarged head that acts as a stop adapted to bear against anexternal portion of the cranium surrounding the hole. The enlarged headmay have at least one suture orifice therein to enable the connector tobe sutured to the cranium to prevent movement of the connector withinthe hole after insertion into the hole.

[0011] This invention also includes a self-sealing catheter forinsertion through a bore hole in a cranium of a patient. It comprises anelongated tubular catheter body sized to fit through the bore hole inthe cranium and a sealing member mounted on the exterior of the catheterbody made of a material that deforms upon insertion into the bore hole.The sealing member may have along at least a portion thereof an outerdiameter larger than the bore hole to provide a substantially fluidtight seal between said bore hole and the sealing member upon insertionof the catheter into the bore hole. The sealing member may include athread element that facilitates advancement into the bore hole. Thisthread element may comprise a helical bead formed on the exterior of thecatheter body. The helical bead may be formed of silicone. Alternately,the sealing member may comprise a generally tubular sleeve having anarrow passageway that fits snugly around the catheter body and anenlarged head sized larger than the bore hole. An exterior surface ofthe tubular sleeve may be conical, having a narrow distal end andthreads are formed on the exterior surface. The tubular sleeve may havea cleft that permits the sleeve to constrict upon insertion into thebore hole. The tubular catheter body may be moveable axial within thepassageway prior to screwing the threaded element into the hole.

[0012] These features are not listed in any rank order nor is this listintended to be exhaustive.

[0013] This invention also includes methods for relieving fluid pressureresulting from fluid collecting within a body cavity. In these methods,a hole provides access to the cavity and the fluid is drained from thecavity by inserting a drainage catheter through the hole so that adistal end is lodged within the cavity and a proximal end extends fromthe cavity. The proximal end has a one-way pressure-responsive valvethereat with an outlet and an inlet in fluid communication with thedrainage catheter to permit pressure-regulated flow of fluid from thecavity through the outlet of the valve. The fluid that passes throughthe valve is collected in a reservoir with an inlet in communicationwith the outlet of the valve. The proximal end of the catheter, theinlet and outlet of the valve, and the inlet of the reservoir arepositioned nearby each other so that there is essentially no hydrostaticpressure affecting to flow of fluid from the cavity of a patient.Typically, the distance between the outlet of the valve and the inlet ofthe reservoir is no greater than 3 inches. Typically, the proximal endof the catheter, the inlet and outlet of the valve, and the inlet of thereservoir are at substantially the same height.

[0014] One method is specific for collecting fluid within a cavityformed at least in part by the ventricle walls of the brain enclosedwithin the cranium of a patient. A hole is formed in the cranium toprovide access to the cavity and a plug-type connector sized to fitsnugly in the hole to prevent any substantial leakage of fluid past theconnector. The connector may have a passageway therein. An elongateddrainage catheter passes through the passageway so that a first end ofthe catheter is seated within the cavity and a second end of thecatheter is external to the cranium. The first end may have at least onedrainage aperture therein. Typically, the drainage catheter fits snugwithin the passageway to prevent any substantial leakage of between thecatheter and the passageway. The flow of fluid from the cavity iscontrolled so that the fluid pressure within cavity is maintained at alevel that prevents the ventricle walls form making substantial contactwith the drainage apertures. In one embodiment, a connector is used ofthe type discussed above.

DESCRIPTION OF DRAWINGS

[0015] Some embodiments of this invention, illustrating all itsfeatures, will now be discussed in detail. These embodiments depict thenovel and non-obvious drainage system and methods of this invention asshown in the accompanying drawings, which are for illustrative purposesonly. These drawings includes the following figures (Figs.), with likenumerals indicating like parts:

[0016]FIG. 1 is a schematic illustration of a prior art externalintracranial drainage system having a drainage catheter inserted intothe cranium of the patient (shown in phantom);

[0017]FIG. 2 is a perspective view of an external intracranial drainagesystem of the present invention mounted on the head of a patient (shownin phantom);

[0018]FIG. 3 is a perspective view of the drainage system of FIG. 2 withthe reservoir disconnected;

[0019]FIG. 4 is a side elevational view of a portion of the drainagesystem of FIG. 2;

[0020]FIG. 5 is a partial sectional view of a drainage catheter of thesystem of FIG. 2 inserted through a bore hole in the cranium;

[0021]FIG. 5A is a cross-sectional view through the drainage cathetertaken along line 5A-5A of FIG. 5;

[0022]FIG. 6 is a perspective view of a cranium connector or seal thatmounts on the catheter of FIG. 5;

[0023]FIG. 7 is a partial sectional view of an alternative drainagecatheter for use in the system of FIG. 2 inserted through a bore hole inthe cranium;

[0024]FIG. 8 is a perspective view of an alternative externalintracranial drainage system of the present invention having a tubularreservoir and mounted on the head of a patient (shown in phantom);

[0025]FIG. 8A is a cross-sectional view through the tubular reservoirtaken along line 8A-8A of FIG. 8;

[0026]FIG. 9 is a perspective view of an external drainage system of thepresent invention having an annular reservoir and mounted for drainageof a swollen knee; and

[0027]FIG. 9A is a cross-sectional view through the annular reservoirtaken along line 9A-9A of FIG. 9.

[0028]FIG. 10 is an exploded perspective view of the pressure-responsivevalve used in the system of this invention.

[0029]FIG. 11 is a side view with sections broken away showing theplug-type connector used in one embodiment of the system of thisinvention.

[0030]FIG. 12 is a schematic view showing the plug-type connectordepicted in FIG. 11 inserted into a bore hole in the cranium of apatient with a distal end lodged within a cavity formed by the ventriclewalls of the patient's brain.

PRIOR ART Treatment of Hydrocephalus

[0031] The treatment of hydrocephalus aims to reduce the intracranialpressure to normal, physiological values and thereby also reduce theamount of CSF towards normal, physiological values. Typically, CSF isdrained from the ventricular system to another resorption site,bypassing the pathological obstruction by use of a CSF shunt. The mostsuitable diversion sites for CSF have been found to be the right atriumof the heart and the peritoneal cavity.

[0032] Generally, fluid shunt systems include a valve mechanism tohinder retrograde flow in the drainage system which could occur due topressure differences between the intracranial cavity and the resorptionsite, e.g. in connection with increased chest and/or abdominal pressurein connection with e.g cough or defecation. One shunt system includes aventricular catheter inserted into a ventricle of the brain, aperitoneal catheter inserted into the peritoneal region for discharge ofthe fluid, and a valve mechanism therebetween. Exemplary shunt systemsinclude U.S. Pat. No. 5,928,182 to Kraus, et al. The valve and cathetersof such systems are typically attached to or implanted under thepatient's scalp and left in place for significant periods.

[0033] Under certain circumstances, it is desirable to treathydrocephalus by draining the excess fluid from the ventricles of thebrain to a collection receptacle that is external to the body. This istypically the case of surgically induced hydrocephalus which may be onlya temporary problem and would not require a totally implanted shuntingsystem. In such a case, an external shunt or drainage system isdesirable. One such system is disclosed in U.S. Pat. No. 5,772,625 toKrueger, et al.

[0034] External intracranial fluid drainage involves drilling a borehole through the cranium and inserting a drainage catheter to theaffected location. The drainage catheter has multiple apertures on itsdistal end through which the fluid automatically drains due to itsexcess pressure, or due to a siphoning effect. Sometimes the drainagecatheter remains in place for extended periods of time so as to relievepressure as it builds up. Typically, the amount and timing of fluiddrainage is regulated by controlling the pressure differential betweenthe proximal and distal ends of the catheter. An incorrect pressuredifferential results either in too much fluid drainage or inadequatedrainage. The proper pressure differential permits fluid drainage onlywhen the pressure within the cranium builds to an unacceptable level,and that pressure is preferably accounted for when calibrating thedrainage system.

[0035]FIG. 1 illustrates a conventional intracranial pressure releasesystem 20 much like that disclosed in U.S. Pat. No. 5,772,625 toKrueger, et al. This system 20 operates on hydrostatic pressure and hasa drainage catheter 22 with a plurality of drainage apertures 24 on itsdistal end 28 a inserted through a scalp incision 26 of a patient. Thedrainage catheter 22 has a proximal end 28 b that attaches to the top ofa fluid column 30. One or more medical connectors disposed between theproximal end 28 b and distal end 28 a of the drainage catheter 22provide ports 21 for sampling or infusion, such as sampling port 32. Aone-way valve is typically connected to drainage catheter 22 to preventretrograde flow. The fluid column 30 is height adjustable with respectto a stationary pole 34 and has an outlet 36 in communication with aninlet 38 of a reservoir bag 40 through a three-position stop cock SC.With the stop cock SC open, fluid drains through the catheter 22, thefluid column 30, and into the reservoir bag 40 depending on theelevation of the fluid column relative to the distal end 28 a. Thus, theheight of the fluid column 30 regulates the pressure differentialthrough the drainage catheter 22.

[0036] The system 20 illustrated in FIG. 1 is relatively cumbersome andessentially relegates the patient to the hospital bed. As the pressurewithin the patient's cranium fluctuates, the height of fluid column 30must be adjusted to maintain the proper pressure differential throughthe catheter 22. Moreover, movement of the patient changes the relativeelevation of the proximal and distal ends of catheter, and thus altersthe pressure differential therethrough. Consequently, a nurse orattendant must move the column each time the patient wishes to move forexample for a seated to a lying posture or vice versa. This prior artsystem is both cumbersome, inconvenient to the patient, and requires anurse to spend time attending to the patient.

DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THIS INVENTION

[0037] One embodiment of the intracranial drainage system 50 of presentinvention is shown in FIG. 2 mounted to the head 52 of a patient. FIG. 3shows this system 50 in isolation and partially exploded. The drainagesystem 50 comprises a drainage catheter 54 having a distal end 54 a witha plurality of drainage apertures 56 therein. A proximal end 58 of thedrainage catheter 54 is in fluid communication with an inlet 60 a of aone-way pressure-responsive valve 60. The proximal end 58 may connectdirectly to the inlet 60 a of the pressure-responsive valve 60, or maybe connected via an intermediate three-way junction or stock cock 62having a sampling port 64. A mating pair of connectors 66 may beutilized so that the drainage catheter 54 can be decoupled from theremainder of the system if necessary.

[0038] A drainage tube 70 attaches to an outlet 60 b of thepressure-responsive valve 60 and has a coupling 72 on its opposite endthat mates with an inlet to 74 of a reservoir bag 76. The system 50 isshown assembled in FIG. 2 and attached to the head 52 of the patient. Itcan be seen that the proximal end 58 of the drainage catheter 54, thepressure-responsive valve 60, and the inlet tube 74 to the reservoir bag76 are generally at the same elevation or height above ground level whenthe patient's head 52 is upright. Specifically, the drainage apertures56 at the distal end of the catheter 54, the reservoir inlet 74, and thepressure-responsive valve 60, including its inlet 60 a and outlet 60 ball lie in substantially same plane P and the reservoir inlet 74 andinlet 60 a and outlet 60 b all lie along the line L which is in theplane P. The pressure at the inlet 60 a is the intracranial pressure andthe pressure at the outlet 60 b is atmospheric. Because the reservoirinlet 74 and the outlet 60 b are

[0039] As shown in FIG. 10 the pressure-responsive valve 60 is designedto be sensitive to changes in pressure to open and close. This valve 60has an hour shaped resilient membrane 150 folded to form an elongatedslit type opening 152 comprising the outlet 60 b. The folded membrane150 is between a pair of plates 154 and 156 that maintain it in tensionto normally closed the opening 152. The inlet 60 a of thepressure-responsive valve 60 comprises a tube 158 having one end 158 ain communication with the proximal end of the catheter 54 through thestop cock 60 and another end 158 b in communication with a venturichamber 162. Preferably, the venturi chamber 162 has a trapezoidalconfiguration with sidewalls that taper inward at an angle of about 10°.The particulars of such a pressure-responsive valve 60 can be found inU.S. Pat. Nos. 5,071,408 and 5,743,869, both to A. Mateen Ahmed, thedisclosures of which are hereby expressly incorporated by reference.

[0040] The components of the system 50 are mounted on structure thatfits to the patient's head 52 and maintains the components at theirrespective elevations. More particularly, the head mounting structure isa headband H that includes a horizontal strap 80 having an adjustmentbuckle 82, and a vertical strap 84 having a length that can be adjustedusing mating hook and loop fasteners 86, or other similar expedient. Thethree-way junction 62 and pressure-responsive valve 60 desirably attachto a rear portion of the horizontal strap 80 as shown. These components,typically made of polymeric material, may be glued, or attached usingstitches, or more securely using rivets to the horizontal strap 80. Thereservoir bag 76 hangs generally vertically downward from a verticalattachment strap 90 sewn to the horizontal strap 80 with stitching 92.Desirably, the reservoir bag 76 is detachable from the strap 90 such aswith a pair of mating snaps 94, 96 on a flange 98 of the reservoir bagand the strap, respectively. Because the coupling 72 on the drainagetube 70 can be disengaged from the inlet tube 74, the reservoir bag 76can thus be removed when full and replaced with an empty bag.Alternatively, fluid within the reservoir bag 76 may be drained throughan outlet tube 100.

[0041] With reference again to FIG. 2, the approximate location of thedistal end 54 a of the drainage catheter 54 after insertion in thecranium is ideally in the plane P, but may be slightly above or belowthis plane P. The particular location within the patient's head 52 fromwhich fluid must be drained varies, though once inserted, the drainageapertures 56 remain at a substantially fixed elevation with respect tothe pressure-responsive valve 60 as long as the patient's head 52remains stationary. However, even if the patient changes from a sittingto a lying down position, for example, the distances are so small thatthe relative elevations of the drainage apertures 56 and thepressure-responsive valve 60 remain essentially constant. In otherwords, the proximal end 58 of the catheter 54, the inlet 60 a and outlet60 b of the valve 60, and the inlet 74 of the reservoir 76 arepositioned nearby each other so that there is essentially no hydrostaticpressure affecting to flow of fluid from the cavity of a patient.Typically, the distance between the outlet 60 b of the valve 60 and theinlet 74 of the reservoir 76 is no greater than about 3 inches.Typically, the proximal end 58 of the catheter 54, the inlet 60 a andoutlet 60 b of the valve 60, and the inlet 74 of the reservoir 76 are atsubstantially the same height. The positioning minimize any hydrostaticpressure in the system affecting to flow of fluid from the cavity in thecranium of the patient. In a preferred embodiment, the system 50maintains the drainage apertures 56 at substantially the same elevationas the pressure-responsive valve 60 and the inlet 74 to the reservoirbag 76, so that the drainage apertures 56 at the distal end of thecatheter 54, the reservoir inlet 74, and the pressure-responsive valve60, including its inlet 60 a and outlet 60 b, all lie in substantiallysame plane P. Because the relative elevations of these variouscomponents of the drainage system 50 are substantially fixed, the systemcan be calibrated to relieve fluid pressure from within the cranium.That is, the pressure-responsive valve 60 permits fluid flowtherethrough upon a predetermined pressure buildup within the drainagecatheter 54. The system 50 can be calibrated so that fluid flows throughthe drainage catheter 54 upon reaching a threshold pressure differentialacross the pressure-responsive valve 60. In this system, the inlet 60 aof the valve 60 is at the internal fluid pressure with the cranium ofthe patient and the outlet 60 b is at atmospheric pressure. The valve 60is calibrated to open when the differential in pressures between theinlet 60 a and the outlet 60 b of the valve 60 is at a predeterminedlevel. Below this level the valve automatically closes. In this way,fluid is only removed from the cranium due to abnormal pressures.

[0042] As seen in FIGS. 2 and 3, and in more detail in FIGS. 5 and 6,the drainage catheter 54 incorporates an exterior cranium connector-seal110 thereon. As depicted in FIG. 5 a bore hole 114 is drilled into thecranium 112 and a cranium connector-seal 110 is inserted into this borehole. The cranium connector-seal 110 has a cylindrical through bore orpassageway 124 therein through which passes the drainage catheter 54.The cranium connector-seal 110 is shown isolated in FIG. 6 and includesa generally tubular sleeve 120 with an enlarged flange or head 122 on aproximal end held in position after insertion into the bore hole 114 bysutures 132. The sleeve 120 and head 122 together defined the passageway124 that receives the exterior of the drainage catheter 54. A medicalgrade adhesive may be used to fasten the connector-seal 110 to theexterior of the drainage catheter 54. An elongated V-shaped slit 126 maybe formed in the sleeve 120 so that passageway 124 can be sized slightlysmaller than the catheter 54 and the connector-seal 110 expands to fitover the catheter in an interference fit. In this regard, the craniumconnector-seal 110 may be mounted on the catheter 54 merely by afriction fit and does not have to be fastened to the catheter 54 with anadhesive.

[0043] The exterior surface of the sleeve 120 tapers inward due to theslit 126 being closed upon inserting the cranium connector-seal 110 intothe bore hole 114. There are a series of raised fingers 130 parallel tothe longitudinal axis X of the sleeve 120 that assist in gripping theside wall 114 a of the bore hole 114. The cranium connector-seal 110 ismade of a soft material that fills the annular space between theexterior of the catheter 54 and the cranium bore 114. For example, theconnector-seal 110 may be made of a soft silicone,polytetrafluoroethylene (PTFE or Teflon), Dacron, polypropylene, orpolyamide. The bore hole 114 may have to be enlarged from holes formedfor catheters without the connector-seal 110. The conventional techniqueis to size the bore hole 114 slightly larger than the catheter andutilize a cementitious material or fibrin glue to fill the annularspace. When using the cranium connector-seal 110, the bore hole 114 maybe enlarged by 20% or more, from 5 to 7 millimeters (mm) for example. Inone embodiment, the cranium connector-seal 110 is formed of twodifferent materials, or at least two different material properties, suchthat the surface of the passageway 124 is relatively stiffer than theouter surface threads 130. In this way, the connector-seal 110 moresecurely mounts over the catheter 54, yet still is pliable enough toconform to the generally irregular cranium bore 114.

[0044]FIGS. 11 and 12 depict an alternate cranium connector, the craniumconnector-seal 200, which may also may be made of a soft silicone,polytetrafluoroethylene (PTFE or Teflon), Dacron, polypropylene, orpolyamide. The cranium connector-seal 200 comprises an enlarged head 202and a truncated conical body 204 with a helical thread 206 on theexterior surface of the truncated conical body and a passageway 212through the body 204 for the catheter 54. There are openings 208 in thehead 202 that allow the connector-seal 200 to be sutured with sutures132 (FIG. 12) to the cranium 112 after insertion into the bore hole 114.Prior to inserting the cranium connector-seal 200 into the bore hole114, the catheter 54 is inserted through passageway 212, limiting thelength 1 of the distal end portion 54 c (FIG. 12) of the catheter 54 toabout 6 to about 14 inches.

[0045] In use, the bore hole 114 is first drilled through the cranium112. The distal end portion 54 c of the catheter 54 having the drainageapertures 56 therein is then inserted through the passageway 212 in thecranium connector-seal 200 and the cranium connector-seal is insertedinto the bore hole 114 with the narrow distal end of the conical body204 fitting into the bore hole 114. Because of the conical shape of thebody 204, the distal end of this body fits into the bore hole 114although its proximal end is sized somewhat larger. When resistance ismet, the entire catheter 54 with cranium connector-seal 200 thereon isadvanced by gentle rotation so that threads 206 engage the side wall 114a of the bore hole 114. As with any such operation, the threads 206 helpadvance the connector-seal 200 into the bore hole 114. The head 202 maybe provided with flats with which a wrench or other such tool may engageto help seat the cranium connector-seal 200 into the bore hole 114.Eventually, the head 202 abuts the exterior of the cranium 112, and thesutures 132 may be sewn to the cranium 112 to prevent reverse rotation.Because a secure and fluid tight seal is thus created, there is noleakage around the catheter 54. This means the intracranial pressure ismore accurately transmitted without loss through the catheter 54. Thisresults in a more consistent and accurate regulation of the fluid flowthrough the pressure-responsive valve 60.

[0046] It should be noted that the length of the catheter 54 thatextends through the cranium (i.e., is distal end portion 54 c to thecranium connector-seal 200) is shorter than prior art systems. Manysystems have no positive depth gauge, as the catheter-mountedconnector-seal 200 provides, and may be inserted up to 9 inches into thecranial space. Consequently, the catheter may touch brain tissue andinduce growth of such tissue onto the apertures 56 of the catheter 54.The present invention, on the other hand, avoids or reduces thelikelihood of this problem, because the pressure within the cavity keepsthe ventricle walls 230 (FIG. 12) from touching the distal end portion54 c of the catheter 54. The present invention also employs a relativelyshort length of the catheter 54 distal to the connector-seal 200, forinstance only about 3.5 inches in most cases.

[0047]FIG. 7 illustrates an alternative self-sealing catheter 140 forinsertion through a bore hole in a cranium 142. As before, the catheter140 includes an elongated hollow tube 144 preferably having a pluralityof drainage apertures 146 on its distal end. The catheter 140 furtherincludes a relatively soft helical sealing member 148 on its exteriorand extending an axial length adjacent the distal end. In an exemplaryembodiment, the sealing member 148 comprises a soft silicone rib thatattaches to and projects outward from the catheter tube 144. The rib 148may be attached using heat or ultrasonic welding. By sizing the borehole through the cranium 142 just slightly larger than the diameter ofthe tube 144, an interference fit is created between the outwardlyprojecting sealing member 148 and the side wall of bore hole. Because ofits helical arrangement, the sealing member 148 acts as a thread ofsorts that helps advance the catheter 140 into sealing engagement withthe bore hole.

[0048] An alternative external drainage system 160 of the presentinvention shown in FIG. 8 replaces the conventional reservoir bag with ahoop-shaped reservoir 162. As before, the system 160 includes a drainagecatheter 164 having a cranium seal 166 thereon and connected at aproximal end to a stop cock or three-way port 168. A pressure-responsiveone-way valve 170 similar to that shown in FIG. 10 is positioned in thefluid flow line between the three-way port 168 and an inlet 172 to thereservoir 162. The reservoir 162, seen in cross-section in FIG. 8A, issized to rest horizontally on the patient's head 174. For this purpose,several sizes of reservoir 162 may be made available. An adjustablevertical strap 176 is secured with loops on either side of the reservoir162 to secure the system 160 in place. The hoop-shaped reservoir 162 issomewhat less cumbersome than a conventional reservoir bag as describedabove. As in the earlier-described embodiment, the relative elevationsof the drainage catheter 164, one-way valve 170, and reservoir inlet 172remain fixed in essentially the same plane even upon movement of thepatient's head.

[0049]FIGS. 9 and 9A illustrates a drainage system 180 of the presentinvention in use in a location other than the cranium, in particular toremove fluid swelling 182 from the knee joint 184. The system 180includes a drainage catheter 190 in fluid communication with an inlet192 of an annular reservoir 194. Although not shown, apressure-responsive one-valve will be positioned in series between thedrainage catheter 190 and the reservoir 194. The reservoir 194 isillustrated in cross-section FIG. 9A and is desirably shaped in a narrowoval so as to have a lower profile around the leg and be lessconspicuous when worn beneath pants. Once again, the proximity of thecomponents of the system 180 means that their relative elevations aresubstantially the same, which provides consistent static pressuredifferentials across the one-way valve.

Scope of the Invention

[0050] The above presents a description of the best mode contemplated ofcarrying out the present invention, and of the manner and process ofmaking and using it, in such full, clear, concise, and exact terms as toenable any person skilled in the art to which it pertains to make anduse this invention. This invention is, however, susceptible tomodifications and alternate constructions from that discussed abovewhich are fully equivalent. Consequently, it is not the intention tolimit this invention to the particular embodiments disclosed. On thecontrary, the intention is to cover all modifications and alternateconstructions coming within the spirit and scope of the invention asgenerally expressed by the following claims, which particularly pointout and distinctly claim the subject matter of the invention:

1. A system for relieving pressure resulting from fluid collecting in acavity in the cranium of a patient, comprising: a drainage catheterhaving a first end adapted to be inserted into the cavity and a secondend that is external to the cranium; a connector adapted to be attachedto the cranium that holds the first end of the catheter in position inthe cavity and prevents leakage of fluid past the connector, so thatessentially all the fluid flowing from the cavity passes through thecatheter with essentially no fluid bypassing the catheter and flowingaround the connector; a one-way pressure-responsive valve with an inletin fluid communication with the catheter to permit pressure-regulatedflow of fluid from the cavity through the catheter; and a reservoirhaving an inlet in fluid communication with an outlet of thepressure-responsive valve so as to receive the fluid that passes throughthe catheter.
 2. The system according to claim 1 where thepressure-responsive valve includes a pair of membrane members thatoverly each other to form a slit type opening at the outlet, saidmembrane members being in tensioned to close the opening when thedifferential in pressure between the inlet and outlet is at apredetermined difference and to open said opening when the differentialin pressure between the inlet and outlet is greater than saidpredetermined difference.
 3. The system according to claim 2 where thepressure-responsive valve includes a venturi chamber that has one end incommunication with the second end of the catheter and another end incommunication with the inlet of the reservoir.
 4. The system accordingto claim 1 where the connector is integral with the catheter andincludes a thread element on an external surface of the catheter at ornearby the first end of the catheter.
 5. The system according to claim 1where the connector fits snugly into a hole in the cranium to preventany substantial leakage of fluid past the connector, said connectorhaving a passageway therein through which the drainage catheter extendsso that said second end of the catheter is external to the cranium. 6.The system according to claim 5 where the passageway is formed by asubstantially cylindrical wall member with a cleft therein.
 7. Thesystem according to claim 5 where the connector has a body with externalthreads thereon enabling the connector to be screwed into the hole. 8.The system according to claim 7 where the body is made of a materialthat deforms upon compression and has a substantially truncated conicalshape sized to fit into the hole and compress as the connector isscrewed to the hole to provide a substantially fluid tight seal betweenthe hole and the body, said passageway being constricted as connector isscrewed into the hole to provide a substantially fluid tight sealbetween the catheter and the passageway.
 9. The system according toclaim 8 where the body has an enlarged head that acts as a stop adaptedto bear against an external portion of the cranium surrounding the hole,said enlarged head having at least one suture orifice therein to enablethe connector to be sutured to the cranium to prevent movement of theconnector within the hole after insertion into the hole.
 10. The systemaccording to claim 1 where the outlet of the catheter, the inlet andoutlet of the valve, and the inlet of the reservoir are substantially ina common plane.
 11. The system according to claim 1 where the outlet ofthe catheter, the inlet and outlet of the valve, and the inlet of thereservoir are nearby each other so that there is essentially nohydrostatic pressure in the system affecting to flow of fluid from thecavity in the cranium of a patient.
 12. The system according to claim 11where the distance between the outlet of the valve and the inlet of thereservoir is no greater than 3 inches.
 13. The system according to claim1 where drainage catheter, pressure-responsive valve, and reservoir areconnected to a mounting member that is adapted to be detachably coupledto the head of the patient.
 14. A connector that fits snugly into a holein the cranium of a patient to prevent any substantial leakage of fluidpast the connector, said connector adapted to hold a drainage catheterin position with a first end of the catheter inserted into a cavity inthe cranium and a second end that is external to the cranium, saidconnector comprising a body having a substantially truncated conicalshape sized to fit into the hole, external threads on an externalsurface of the body enabling the connector to be screwed to the hole,and a passageway therein for insertion therethrough of the drainagecatheter so that said second end of the catheter is external to thecranium, said body being made of a material that deforms uponcompression and compress as the connector is screwed to the hole toprovide a substantially fluid tight seal between the hole and the body,said passageway being constricted as connector is screwed to the hole toprovide a substantially fluid tight seal between a catheter extendingtherethrough and the passageway.
 15. The connector of claim 14 where thebody has an enlarged head that acts as a stop adapted to bear against anexternal portion of the cranium surrounding the hole, said enlarged headhaving at least one suture orifice therein to enable the connector to besutured to the cranium to prevent movement of the connector within thehole after insertion into the hole.
 16. In combination, a drainagecatheter having a first end adapted to be inserted into a cavity in thecranium of a patient and a second end that is external to the cranium,and a connector adapted to be inserted into a hole in the cranium andsized to fit snugly into the hole in the cranium to prevent anysubstantial leakage of fluid past the connector, said connector having apassageway therein through which the drainage catheter extends so thatsaid second end of the catheter is external to the cranium.
 17. Thecombination according to claim 16 where the passageway is formed by asubstantially cylindrical wall member with a cleft therein.
 18. Thecombination according to claim 16 where the connector has a body withexternal threads thereon enabling the connector to be screwed to thehole.
 19. The combination according to claim 18 where the body is madeof a material that deforms upon compression and has a substantiallytruncated conical shape sized to fit into the hole and compress as theconnector is screwed to the hole to provide a substantially fluid tightseal between the hole and the body, said passageway being constricted asthe connector is screwed into the hole to provide a substantially fluidtight seal between the catheter and the passageway.
 20. The combinationaccording to claim 19 where the body has an enlarged head that acts as astop adapted to bear against an external portion of the craniumsurrounding the hole, said enlarged head having at least one sutureorifice therein to enable the connector to be sutured to the cranium toprevent movement of the connector within the hole after insertion intothe hole.
 21. A portable system for relieving fluid pressure from a bodycavity of a patient, comprising: a drainage catheter for insertion intothe body cavity; a one-way pressure-responsive valve with an inlet influid communication with the drainage catheter to permitpressure-regulated flow of fluid from the body cavity through thecatheter; and a reservoir having an inlet in fluid communication with anoutlet of the pressure-responsive valve so as to receive the fluid thatpasses therethrough; said drainage catheter, pressure-responsive valve,and reservoir connected to a mounting member that is adapted to bedetachably coupled to the patient nearby the body cavity.
 22. The systemof claim 21 where the body cavity is within the cranium and the mountingmember comprises a headband.
 23. The system of claim 22 where theheadband includes a first component sized to fit around thecircumference of the patient's head, and a second component connected byopposed ends thereof to the first component and sized to fit over thetop of the patient's head.
 24. The system of claim 23 including areleasable chin strap to permit easy removal of the system.
 25. Thesystem of claim 21 where the first component is adjustable to differentpatient head circumferences.
 26. The system of claim 22 where theheadband comprises at least partially hollow member that functions asthe reservoir.
 27. The system of claim 26 where the hollow member ishoop-shaped.
 28. The system of claim 22 where the reservoir isdetachably connected to the headband.
 29. The system of claim 28 wherethe headband and reservoir are connected by a snap-type connector. 30.The system of claim 22 where the pressure-responsive valve includes apair of membrane members that overly each other to form a slit typeopening at the outlet, said membrane members being in tensioned to closethe opening when the differential in pressure between the inlet andoutlet is at a predetermined difference and to open said opening whenthe differential in pressure between the inlet and outlet is greaterthan said predetermined difference.
 31. The system of claim 21 where theoutlet of the pressure-responsive valve is at substantially atmosphericpressure and the inlet pressure-responsive valve is at the pressurewithin the body cavity, said valve opening when the differential betweenatmospheric pressure and the pressure within the body cavity exceeds apredetermined difference and closes when said differential is less thansaid predetermined difference.
 32. The system according to claim 31where an outlet of the catheter, the inlet and outlet of the valve, andthe inlet of the reservoir are nearby each other so that there isessentially no hydrostatic pressure in the system affecting to flow offluid from the body cavity.
 33. The system according to claim 32 wherethe distance between the outlet of the valve and the inlet of thereservoir is no greater than 3 inches.
 34. The system of claim 33 wherethe drainage catheter has a distal end with drainage apertures therein,and said distal end of the drainage catheter, reservoir inlet, andpressure-responsive valve are at substantially the same height.
 35. Aportable apparatus for relieving fluid pressure from a body cavity of apatient, comprising: a drainage catheter having a distal end withdrainage apertures; and a substantially ring-shaped hollow reservoirhaving an inlet in fluid communication with the drainage catheter andbeing sized to mount to the patient immediately adjacent the bodycavity.
 36. The apparatus of claim 35 including a one-waypressure-responsive valve interposed between the drainage catheter andthe reservoir inlet to permit pressure-regulated flow of fluid from thebody cavity through the catheter to the reservoir.
 37. The apparatus ofclaim 36 where the pressure-responsive valve includes an inlet, andoutlet, and a pair of membrane members that overly each other to form aslit type opening at the outlet, said membrane members being intensioned to close the opening when a differential in pressure betweenthe inlet and outlet is at a predetermined difference and to open saidopening when the differential in pressure between the inlet and outletis greater than said predetermined difference.
 38. The apparatus ofclaim 35 where the body cavity is within a cranium of a patient.
 39. Theapparatus of claim 38 where the distal end of the drainage catheter, thereservoir inlet, and the pressure-responsive valve are at substantiallythe same height.
 40. The apparatus of claim 39 where the substantiallyring-shaped hollow reservoir extends around to the circumference of thepatient's head.
 41. A self-sealing catheter for insertion through a borehole in a cranium of a patient, comprising: an elongated tubularcatheter body sized to fit through the bore hole in the cranium; and asealing member mounted on the exterior of the catheter body made of amaterial that deforms upon insertion into the bore hole, said sealingmember having along at least a portion thereof an outer diameter largerthan the bore hole to provide a substantially fluid tight seal betweensaid bore hole and the sealing member upon insertion of the catheterinto the bore hole.
 42. The self-sealing catheter of claim 41 where thesealing member includes a thread element that facilitates advancementinto the bore hole.
 43. The self-sealing catheter of claim 42 where thethread element comprises a helical bead formed on the exterior of thecatheter body.
 44. The self-sealing catheter of claim 43 where thehelical bead is formed of silicone.
 45. The self-sealing catheter ofclaim 42 where the sealing member comprises a generally tubular sleevehaving a narrow passageway that fits snugly around the catheter body andan enlarged head sized larger than the bore hole.
 46. The self-sealingcatheter of claim 45 where an exterior surface of the tubular sleeve isconical having a narrow distal end and threads are formed on theexterior surface.
 47. The self-sealing catheter of claim 45 where thetubular sleeve has a cleft that permits the sleeve to constrict uponinsertion into the bore hole.
 48. The self-sealing catheter of claim 42where the sealing member comprises a body member made of a material thatdeforms upon compression and has a substantially truncated conical shapesized to fit into the bore hole and compress as the threaded element isscrewed to the hole to provide a substantially fluid tight seal betweenthe hole and the body, said passageway being constricted as the threadedelement is screwed into the hole to provide a substantially fluid tightseal between the catheter and the passageway.
 49. The self-sealingcatheter of claim 48 where the body member has an enlarged head thatacts as a stop adapted to bear against an external portion of thecranium surrounding the hole, said enlarged head having at least onesuture orifice therein to enable the sealing member to be sutured to thecranium to prevent movement of the catheter within the hole afterinsertion into the hole.
 50. The self-sealing catheter of claim 49 wherethe tubular catheter body is moveable axial within the passageway priorto screwing the threaded element into the hole.
 51. A portable systemfor relieving fluid pressure resulting from the fluid collecting in acavity in the cranium of a patient, comprising: means for draining fluidfrom the cavity including a drainage catheter having a first portionthat is at least 4 inches in length for insertion into the cavity and asecond portion that extends from the cavity; a one-waypressure-responsive valve connected to the second portion with an outletand an inlet in fluid communication with the drainage catheter to permitpressure-regulated flow of fluid from the cavity through the outlet ofthe valve; means for collecting the fluid that passes through the valveincluding an inlet in communication with the outlet of the valve; andmeans for detachably mounting to the patient nearby the cavity thecollecting means and the drainage catheter, including thepressure-responsive valve connected thereto.
 52. The system of claim 51where the distal end of the drainage catheter, collecting means inlet,and pressure-responsive valve are at substantially the same height. 53.A method of relieving fluid pressure resulting from fluid collectingwithin a cavity formed at least in part by the ventricle walls of thebrain enclosed within the cranium of a patient, comprising: forming ahole in the cranium to provide access to the cavity; inserting into thehole a plug-type connector sized to fit snugly in the hole to preventany substantial leakage of fluid past the connector, said connectorhaving a passageway therein; passing an elongated drainage catheterthrough the passageway so that a first end of the catheter is seatedwithin the cavity and a second end of the catheter is external to thecranium, said first end having at least one drainage aperture therein,said drainage catheter fitting snug within the passageway to prevent anysubstantial leakage of between the catheter and the passageway; andcontrolling the flow of fluid from the cavity so that the fluid pressurewithin cavity is maintained at a level that prevents the ventricle wallsform making substantial contact with the drainage apertures.
 54. Themethod according the claim 53 where the plug-type connector comprises abody member having a substantially truncated conical shape with anexternal threaded element thereon, said body member being made of amaterial that deforms upon compression to compress as the body member isscrewed to the hole to provide a substantially fluid tight seal betweenthe hole and the body member, said passageway being constricted as thethreaded element is screwed into the hole to provide a substantiallyfluid tight seal between the catheter and the passageway.
 55. A methodof relieving fluid pressure resulting from fluid collecting within abody cavity of a patient, comprising: forming a hole to provide accessto the cavity; draining the fluid from the cavity by inserting adrainage catheter through the hole so that a distal end lodged withinthe cavity and a proximal end extending from the cavity; said proximalend having a one-way pressure-responsive valve thereat with an outletand an inlet in fluid communication with the drainage catheter to permitpressure-regulated flow of fluid from the cavity through the outlet ofthe valve; collecting the fluid that passes through the valve in areservoir with an inlet in communication with the outlet of the valve;and positioning the proximal end of the catheter, the inlet and outletof the valve, and the inlet of the reservoir nearby each other so thatthere is essentially no hydrostatic pressure affecting to flow of fluidfrom the cavity of a patient.
 56. The method according the claim 55where the distance between the outlet of the valve and the inlet of thereservoir is no greater than 3 inches.
 57. The method according theclaim 56 where the proximal end of the catheter, the inlet and outlet ofthe valve, and the inlet of the reservoir are at substantially the sameheight.